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Gym Fitness center Personal trainer Physical fitness program Women's personal trainerAbout the Club
Located in the heart of Goose Island. We offer Classes, Memberships, and Personal Training for Adults and Youth. Our fitness program is built around the fundamentals of functional training to deliver elite performance, and are designed for all fitness levels.
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Reviews
Barbara Schiffer
★ 5
I’ve spent the majority of my life in fitness spaces (both as a competitive gymnast and now a regular gym goers) and this is by far the best place I’ve trained. I have been working out with Jackie for the last 4 years and it has been such a great experience. She has made sure that previous injuries aren’t aggravated and that new ones don’t occur and truly aims to help you hit your personal goals. All sections of the gym are set up to help you reach your goals and become the best version of yourself. I highly recommend Undefined and training with Jackie!
Source: Google
Samantha Schafer
★ 5
As someone who has spent my entire life in the fitness industry, first as a Division I collegiate tennis player and now an avid gym goer, this is the best gym I have ever been to! Jackie has been my personal trainer for four years and she has kept me injury free through a boxing match, a Hyrox event, and everywhere in between. Their weight room is state of the art. Their turf side is perfect for high-performance training. They have open gym hours, strength classes and one on one training. Look no further for your next gym and train with Jackie to accomplish your next fitness goal!
Source: Google
Isabelle Davis
★ 5
I have followed Jackie from gym to gym for the last 3 years and would follow her to a million more! She has changed my relationship to my health, my body and my life!
Source: Google
Mark Lawrence
★ 5
One of the best gyms in the city hands down literally has best weight and martial arts trainers and had literally everything and place is huge. Boxing 🥊 arena and viewing area ridiculously awesome.
Source: Google
David Abouassi
★ 5
Never thought that I would enjoy working out ever in my life. Coach Billy change that for me. Not only for me, but for my wife & son. He pushes you to limits you never thought you had & gives you that courage to push yourself. I’m thankful for him. My son & wife & I love it!!! 💪🏻
Source: Google
Catharine Aiura
★ 5
I am an undefeated professional boxer (6-0) with Coach Billy and Undefined Chi preparing me for my boxing matches. The level of expert coaching that is provided by this gym and this team under this vision and leadership is unmatched. The facilities are state of the art, massive, and honestly the most varied as far as type, quantity, and specificity of equipment which can match any goal or movement that is necessary. (Never waiting for a squat rack here either haha) Above and beyond the unequaled coaching that can elevate even the top 1% of competitors into the 1% of 1%, there are many other aspects that make this gym stand out. One of them is the community; The ethos that the leadership stands staunchly on guides the tone of the entire gym and therefore attracts community members that are kind, driven, supportive, intelligent, community focused, and goal driven. This type of community raises me to higher levels because we all raise each other up, all the while being supported and pushed by incredible leadership that truly cares. In addition to and complimenting the incredible coaching of Coach Billy, Coach Jackie is a powerhouse of knowledge, empathy, and leadership and exudes everything qualitatively and quantitatively anyone could ask for in a strong coach. Every puzzle piece is assembled here and is one of the main power plays that has and will keep me on track for a world title. I'm telling you, check this gym out!!!! See you tomorrow ;)
Source: Google
Trae Bell
★ 5
Truly a hidden gem. Pun intended
Source: Google
Arnold Castro
★ 5
Trained at this gym with Coach Billy for my last professional boxing fight and was in the best shape I have ever been! The gym has everything you need and coach Billy is the best trainer for someone who is serious about training.
Source: Google
Edward Kang
★ 5
Training at Undefined has truly transformed my fitness in ways I never expected. Before joining, I was already active—boxing, jiu jitsu, and working out at home with Les Mills—but it wasn’t until I started working with Coach Billy and the incredible coaching staff at Undefined that I saw a dramatic change. In just a few months, my body and overall fitness have improved beyond what I thought possible—I’m in better shape now than I was in my 30s! Thanks to the support and expert guidance at Undefined, I accomplished my first Hyrox event in the Pro Doubles division at 50 years old, something that previously felt out of reach. The coaches are knowledgeable, encouraging, and genuinely invested in every member’s progress. I couldn’t recommend Undefined and its team highly enough for anyone ready to unlock their full potential.
Source: Google
Richboyrc
★ 5
Simply the place to be if you’re serious about progressing effectively in any sport. Love being a longtime member.
Source: Google
Amy & Ed
★ 5
Undefined has truly been life-changing for our family. Amy and I always thought we knew what to do to stay in shape, but working with Coach Billy has taken us to a whole new level. His attention to detail and the care he shows for everyone in the class are unmatched—even in larger classes, he somehow keeps track of every person. He has this uncanny memory for what weights each of us is lifting for different exercises, which makes every session feel personal and tailored. The gym itself is incredible—packed with every piece of equipment you could imagine. Billy keeps the classes fresh and challenging, constantly varying the workouts so we’re using various equipment each class. Our strength and mobility have improved dramatically. For those training for Hyrox, Coach Billy has all the official Centr Hyrox equipment and knows exactly how to prepare you for race day. On top of that, he’s recently started kids’ strength and conditioning classes, and our 9-year-old absolutely loves them. Billy makes the sessions so much fun that our son is always excited to go. If you’re looking for a gym and a coach who will push you, support you, and keep things exciting, Undefined and Coach Billy is simply amazing.
Source: Google
Prentis Wilbourn
★ 5
I can't hype this place up enough! Billy is hands down the best trainer I've ever had. The energy he brings to every workout is incredible. The atmosphere is infectious, the workouts are focused and intense, and the community is unmatched.
Source: Google
Billy H
★ 5
Source: Google
Mitchell LaBine
★ 5
Undefined Chi is everything you should be looking for in a gym and I could not recommend it enough. The knowledge of all the coaches, the top notch equipment, and an atmosphere that makes you want to improve day in and day out. If you're looking to push yourself physically and mentally look no further!! Sign up TODAY!
Source: Google
Eduardo Camacho
★ 5
World-class gym with World-class trainers!! Highly recommend.
Source: Google
Bryan Alaniz
★ 5
Undefined Chi is truly an amazing gym. Billy is an incredible coach — dedicated, motivating, and always pushing you to be your best — but what makes this place stand out even more is the whole coaching team. Every coach brings something unique, keeps the workouts challenging and interesting, and holds everyone accountable in the best way.
The energy, support, and consistency from all the coaches make you want to show up and put in the work. If you’re looking for a place that will push you, keep you motivated, and help you grow, Undefined Chi is the spot. Highly recommend!
Source: Google
Oscar Castillo
★ 5
Amazing gym! Super welcoming to all levels, and the coaches are great at helping you reach your goals. Totally recommend it!
Source: Google
Ingrid Arroyo
★ 5
I have been working out on my own for about 2 yrs! With some results! But since joining Undefined combined with one way my results have improved by 💯! Best coaches n team they have!
Source: Google
Mike Carreno
★ 5
I’ve been coming to this gym for about two months now. It’s a great gym with solid equipment, a clean setup, and a motivating atmosphere. Always a good workout here. I highly recommend it!!!
Source: Google
Emily Rogowski
★ 5
THE MECA!!!! i’ve visited and been apart of many many gyms in the city and nothing quite compares to UNDEFINED. beginning with the coaches and staff — they go above and beyond to make you feel apart of the community. they remember my goals and upcoming events i have which to me proves they listen and care. the facility itself is brand new, super clean, and well run!! highly recommend!
Source: Google
Mike Hoffenberg
★ 5
Great facility with state-of-the-art equipment. The staff is skilled, friendly, and truly motivated to help you reach your lifestyle goals.
Source: Google